Solar-assisted photodegradation of isoproturon over easily recoverable titania catalysts.

An easily recoverable homemade TiO2 catalyst (GICA-1) has been evaluated during the overall photodegradation process, understood as photocatalytic efficiency and catalyst recovery step, in the solar light-assisted photodegradation of isoproturon and its reuse in two consecutive cycles. The global feasibility has been compared to the commercial TiO2 P25. The homemade GICA-1 catalyst presented better sedimentation efficiency than TiO2 P25 at all studied pHs, which could be explained by its higher average hydrodynamic particle size (3 µm) and other physicochemical surface properties. The evaluation of the overall process (isoproturon photo-oxidation + catalyst recovery) revealed GICA-1 homemade titania catalyst strengths: total removal of isoproturon in less than 60 min, easy recovery by sedimentation, and reusability in two consecutive cycles, without any loss of photocatalytic efficiency. Therefore, considering the whole photocatalytic cycle (good performance in photodegradation plus catalyst recovery step), the homemade GICA-1 photocatalyst resulted in more affordability than commercial TiO2 P25. Graphical abstract.

Open ISEmeter: An open hardware high-impedance interface for potentiometric detection.

In this work, a new open hardware interface based on Arduino to read electromotive force (emf) from potentiometric detectors is presented. The interface has been fully designed with the open code philosophy and all documentation will be accessible on web. The paper describes a comprehensive project including the electronic design, the firmware loaded on Arduino, and the Java-coded graphical user interface to load data in a computer (PC or Mac) for processing. The prototype was tested by measuring the calibration curve of a detector. As detection element, an active poly(vinyl chloride)-based membrane was used, doped with cetyltrimethylammonium dodecylsulphate (CTA(+)-DS(-)). The experimental measures of emf indicate Nernstian behaviour with the CTA(+) content of test solutions, as it was described in the literature, proving the validity of the developed prototype. A comparative analysis of performance was made by using the same chemical detector but changing the measurement instrumentation.

Optimisation of the Fischer-Tropsch process using zeolites for tail gas separation.

This work is aimed at optimizing a Fischer-Tropsch Gas To Liquid (GTL) process by recycling compounds of the expelled gas mixture using zeolites for the separation. To that end, we have performed a computational study on four structures widely used in industry. A range of Si/Al ratios have been explored and the effects of their distribution assessed. The ability of the considered force fields and molecular models to reproduce experimental results has been widely proved in previously reported studies. Since this tail gas is formed by a five-component mixture, namely carbon dioxide, methane, carbon monoxide, nitrogen and hydrogen, molecular simulations present clear advantages over experiments. In addition, the viability of the Ideal Adsorption Solution Theory (IAST) has been evaluated to easily handle further separation steps. On the basis of the obtained results, we provide a separation scheme to perform sequentially the separation of CO2, CH4, CO, N2 and H2.

The use of digital simulation to improve the cyclic voltammetric determination of rate constants for homogeneous chemical reactions following charge transfers.

Cyclic voltammetry (CV) is a very useful electrochemical tool used to study reaction systems that include chemical steps that are coupled to electron transfers. This type of system generally involves the chemical reaction of an electrochemically generated free radical. Published methods exist that are used to determine the kinetics of electrochemically initiated chemical reactions from the measurements of the peak current ratio (i(pa)/i(pc)) of a cyclic voltammogram. The published method requires working curves to relate a kinetic parameter to the peak current ratio. In the presented work, a digital simulation package was used to obtain improved working curves for specific working conditions. The curves were compared with the published results for the first- and second-order chemical reactions following the charge transfer step mechanisms. According to the presented results, the previously published working curve is reliable for a mechanism with a first-order chemical reaction; however, a change in the switching potential requires a recalculation of the curve. In the case of mechanisms with a second-order step (dimerisation and disproportionation), several different views exist on how the second-order chemical term should be expressed so that different values of the constant are obtained. Parameters such as electrode type, electrode area, electroactive species concentration, switching potential, scan rate and method for peak current ratio calculation modify the working curves and must always be specified. We propose a standardised method to obtain the most reliable kinetic constant values. The results of this work will permit researchers who handle simulation software to construct their own working curves. Additionally, those who do not have the simulation software could use the working curves described here. The revelations of the presented experiments may be useful to a broad chemistry audience because this study presents a simple and low-cost procedure for the study of free radicals that otherwise should be studied with more sophisticated and expensive techniques, such as ESR or pulse radiolysis.

Combination of steam explosion and laccase-mediator treatments prior to Eucalyptus globulus kraft pulping.

The effect of a pretreatment consisting of steam explosion (SE) followed by a laccase mediator system (LMS) stage on Eucalyptus globulus kraft pulping has been evaluated and compared with fungal pretreatments. Pretreatment with SE and LMS was more efficient than pretreatments using Pycnoporus sanguineus and Trametes sp. I-62. Steam explosion not only improved the enzyme penetration into the wood chips and shortened the pulping process by 60%, but also extracted around 50% of the hemicelluloses which could be converted into value-added products. The optimal conditions for the LMS treatment were 3h, 3UA/g and 40°C. Compared to SE, the SE/LMS treatment yielded an increase in delignification of 13.9% without affecting pulp properties, provided a similar screened kraft yield, and reduced consumption of chemical reagents Na(2)S and NaOH by 11.5% and 6.3%, respectively. Therefore, SE/LMS is a promising pretreatment for converting the pulp mill into a forest bio-refinery.

Coagulation-Fenton coupled treatment for ecotoxicity reduction in highly polluted industrial wastewater.

A coupled coagulation-Fenton process was applied for the treatment of cosmetic industry effluents. In a first step, FeSO(4) was used as coagulant and the non-precipitated Fe(2+) remaining in dissolution was used as catalyst in the further Fenton process. In the coagulation process a huge decrease in total organic carbon (TOC) was achieved, but the high concentration of phenol derivatives was not diminished. The decrease in TOC in the coagulation step significantly reduces the amount of H(2)O(2) required in the Fenton process for phenol depletion. The coupled process, using a H(2)O(2) dose of only 2 g l(-1), reduced TOC and total phenol to values lower than 40 and 0.10 mg l(-1), respectively. The short reaction period (less than 15 min) in TOC and phenol degradation bodes well for improving treatment in a continuous regime. The combination of both processes significantly reduced the ecotoxicity of raw effluent and markedly increased its biodegradability, thus allowing easier treatment by the conventional biological units in conventional sewage treatment plants (STPs).

Kraft pulp biobleaching using an extracellular enzymatic fluid produced by Pycnoporus sanguineus.

The aim of this work was to obtain a LMS pre-treatment applicable to industrial TCF bleaching. Kraft pulp from Eucalyptus globulus was treated at 40 degrees C/pH 3 and 60 degrees C/pH 5 for 1h using an extracellular fluid enriched in laccase produced by Pycnoporus sanguineus and acetosyringone as mediator (HBT was used as a control mediator) (L). Alkaline extraction (E) and hydrogen peroxide (P) stages were then assayed. The LEP alternative was an efficient sequence to bleach kraft pulp since the enzymatic pre-treatment boosted the subsequent chemical bleaching. The best L pre-treatment was obtained with laccase-acetosyringone at 40 degrees C/pH 3. It reduces kappa number and hexenuronic acids, increases pulp viscosity, lowers hydrogen peroxide consumption down to an 87.4% (94.0% without L) and enhances brightness up to a 59% ISO (51% ISO without L).

Bioremediation of lignosulphonates by lignin-degrading basidiomycetous fungi.

The capability of some ligninolytic fungi to degrade lignosulphonates has been studied. Three lignosulphonates concentrations, three culture media and seven different basidiomycetes in solid-cultures have been assayed to select the conditions for further experiments on submerged cultures. The best results of growth and lignosulphonate decolourization in solid-cultures were obtained with Pycnoporus sanguineus, Coriolus pubescens and Trametes sp. I-62 on Kirk's medium and 1% and 2% of lignosulphonate concentrations. In submerged cultures the lignosulphonate decolourization rate was generally higher when it was added on the 6th day, rather than when it was added from the beginning of the incubation and C. pubescens and P. sanguineus showed again the optimum results of decolourization. Extracellular laccase activity increased with lignosulphonate concentration in all assayed fungi, suggesting that lignosulphonate act as inductors of laccase activity.

[Sinonasal mucosal melanoma]. / Melanomas mucosos nasosinusales.

Mucosal melanomas of the nasal cavity and paranasal sinuses are rare and agresive neoplasms and carries a bad prognosis. The diagnosis may require confirmatory immunohistochemical stains (S-100 protein, HMB-45, vimentin and cytokeratine). The clinical records of 6 patients with the diagnosis of sinonasal melanomas between 1991 and 2005 were retrospectively reviewed. The mean age was 70 years (range 51 to 83 years), there were 2 men and 4 women. Surgery was performed in four patients, adjuvant radiation therapy was used in one patient after local recurrence and chemotherapy in three patients. Three of four patients (75%) had a recurrence after previous treatment (surgery). The actuarial disease-free survival for this group of 6 is 33.3% (2 of 6). Mucosal melanoma of the head and neck remains a difficult disease to treat, with high locoregional recurrence rates and poor prognosis.

[Cutaneous melanoma of the head and neck]. / Melanomas cutaneos de cabeza y cuello.

The clinical records of 20 patients with the diagnosis of cutaneous melanoma of the head and neck treated between 1991 and 2005 were retrospectively reviewed. Advances in diagnostic techniques and treatment have had obvious impact on outcomes in cutaneous melanoma. Cutaneous melanoma of the head of neck is treated with complete surgical resection in early stage disease. Resection margins are determined by the size and depth. Evaluation for regional and distant metastatic disease is necessary in advanced stage disease. Adjuvant therapy may be indicated in regional nodal disease.

Oxidation of C4-hydroxyphenyl 1,4-dihydropyridines in dimethylsulfoxide and its reactivity towards alkylperoxyl radicals in aqueous medium.

This work reports the electrochemical oxidation of three newly synthesized C4-hydroxyphenyl-substituted 1,4-dihydropyridine derivatives in dimethylsulfoxide. The reactivity of the compounds with ABAP-derived alkylperoxyl radicals in aqueous buffer pH 7.4, was also studied. The oxidation mechanism involves the formation of the unstable dihydropyridyl radical, which was confirmed by controlled-potential electrolysis (CPE) and ESR experiments. The final product of the CPE, that is, pyridine derivative, was identified by GC-MS technique for the three derivatives. A direct reactivity of the synthesized compounds toward ABAP-derived alkylperoxyl radicals was found. The pyridine derivative was identified by GC-MS as the final product of the reaction. Results reveal that this type of 1,4-DHPs significantly reacts with the radicals, even compared with commercial 1,4-DHP drugs with a well-known antioxidant ability.

Analyses by GC-MS and GC-MS-MS of the Hantzsch synthesis products using hydroxy- and methoxy-aromatic aldehydes.

EI mass spectra of products of the dihydropyridine Hantzsch synthesis using hydroxy and methoxy aldehydes as starting materials are reported. The reaction products (C-4 hydroxy- and methoxyphenyl-1,4-dihydropyridines and chromeno[3,4,c]-pyridines) were derivatized with N-methyl-N-(trimethylsilyl)-trifluoracetamide to be analyzed by gas chromatographic techniques. Fragmentation pathways for 1,4-dihydropyridines and chromeno-pyridines are proposed. The study provides (mainly through MS-MS technique) useful data for the confirmation of the structure of the compounds and also is a valuable tool for further analytical purposes to follow both photostability and reactivity studies with free radicals for these types of compounds.

[Metastasis to the parotid gland]. / Metastasis en la glandula parótida.

INTRODUCTION: Metastatic disease in the parotid gland has been observed and reported in the literature, and its treatment is controversial. MATERIAL AND METHODS: We review 48 patients with parotid tumors that underwent surgery during 1997-2004. The clinical and histogical features are reviewed. RESULTS: Among these 48, there were 12 cases of metastatic tumors to the parotid (25%). The pathohistological analysis of these tumors revealed that 8 were epidermoid carcinoma (66%), 1 patient was a melanoma (8%), 2 lymphomas below clavicules (16%) and 1 patient with a metastasis of a primary renal cancer. All patients underwent parotidectomy and 10 also cervical neck dissection (6 cases showed cervical metastases). 8 patients received radiotherapy after surgery. CONCLUSIONS: In our study parotid metastases are relatively common in patients submitted for parotid surgery. Often the site of origin of the primary tumor is the facial skin, and the primary tumors most commonly are melanomas or squamous-cell carcinomas, but it is possible distant primary tumors below clavicules.

[Postseptal orbital cellulitis and sinusitis. Descriptive study of 8 cases and literature review]. / Celulitis orbitaria retroseptal y sinusitis. Presentación de 8 casos y revisión de la literatura.

This is a retrospective study of 8 patients with postseptal orbital cellulitis (stages II-V of Chandler) caused by sinusitis during 1999-2003. The variables analyzed in this study included age, sex, delay in diagnosis, aetiology, imaging studies, microbiology specimens collected and treatment. Delays in diagnosis were frecuent. CT was the best radiologic study. Polymicrobial infections were the rule, including anaerobes. 4 patients of 8 needed surgical drainage. A general guideline for the management of periorbital and orbital cellulitis according to the clinical staging of the process is presented.

[Otology manifestations of the Anderson-Fabry disease]. / Manifestaciones otológicas en la enfermedad de Fabry-Anderson.

Anderson-Fabry disease in an inherited X-linked metabolic disorder involving glycosphingolipid metabolism. Few data are available regarding cochlear involvement. Clinical manifestations of Fabry disease appeared on the first decade of life. The prognosis of males with Fabry disease is serious and life expectancy is limited; clinical evolution of heterozygous females is clearly better. We report a family with Fabry disease in several members. The mother, already dead, had two child which have been examined in our department; the male, without a risk of ototoxicity, or acoustic trauma, has progressive hearing loss, tinnitus and dizinness sometimes; the daughter, without a history of deafness, shows unilateral hearing loss on high-tone frequencies. It is important to emphasize these data to those physicians expert in children with Fabry disease because early enzyme replacement therapy intervention should offer increased possibilities of regression of the disease.

[Minimally invasive surgery for treating of complicated fronto-ethmoidal sinusitis]. / Cirugía mínimamente invasiva para el tratamiento de la sinusitis fronto-etmoidal complicada.

OBJECTIVES: Functional endoscopic sinus surgery (FESS) is nowadays the "gold standard" for frontal sinus pathologies, but management of acute situations and the aproach and/or the extent of the surgery perfomed in the frontal recess remains controversial nowadays. MATERIAL AND METHODS: We report our experience in 4 patients with orbital celulitis due to frontal sinusitis who underwent combined external surgery (mini-trephination) and endoscopic sinus surgery. RESULTS: All patients managed sinus patency without any complications. CONCLUSIONS: We found this combined sinusotomy as an easy, effective and reproductible technique in order to resolve the difficult surgical management of complicated frontal sinusitis.

[Lipid profile and hearing-loss aged-related]. / Perfil lipídico de la sordera ligada al envejecimiento.

OBJECTIVES/HYPOTHESIS: Presbycusis is the most prevalent cause of hearing-loss in the older, but pathogenesis is not well-know. The premise of this study is that hyperlipemia increase risk of age-related hearing-loss. PATIENTS AND METHODS: 180 patient more than 65 years-old were studied. All patients had bilateral hearing-loss and no renal, neurological, thyriod or middle-ear pathology. We explored serum levels of cholesterol, HDL, LDL and triglycerides. We performed tonal audimetry in all patients. RESULTS: The 71% of patients has hypercholesteremia and the highest serum levels were detected in 65-69 years-old men (mean media 5,27). Patients with hypercholesteremia had worse hearing-loss than patients with normal lipid serum levels (p < .05). CONCLUSIONS: Our study sugest that hypercholesteremia are associated to age-related hearing-loss, possibly by an atherosclerosis mechanism.

Tannic acid interferes with the commonly used laccase-detection assay based on ABTS as the substrate.

Laccase enzymatic activity in biological samples is usually detected spectrophotometrically through its capacity to oxidize several specific aromatic compounds. One of the most commonly used substrates is the compound 2-2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), which becomes green-blue coloured when it is oxidized by laccase. In this work we study the interference of tannic acid with the spectrophotometric assay to detect laccase by using ABTS as the substrate. Our data show that under the normal reaction conditions of this assay, but in the absence of any catalyst, tannic acid is able to carry out the chemical reduction of the oxidized specie of ABTS, thus decreasing the overall detectable laccase-activity values observed when this enzyme is present in the reaction mixture. Therefore, our results represent an important warning concerning a commonly used method for measuring, detecting or screening laccases in biological samples that may content tannic acid or structural-related molecules.

[Prolonged hospital stay in patient with head and neck cancer: impact of nutritional status and pharyngeal problems]. / Estancia hospitalaria prolongada en pacientes con cáncer de cabeza y cuello: el impacto del estado nutricional y los problemas faríngeos.

UNLABELLED: Patients who underwent surgery for head and neck malignant neoplasms loose two important human functions: phonation and swallowing. The purpose of this study is to determine the impact of nutritional status and pharyngeal problems in hospital stay in these patients. PATIENTS AND METHODS: Fifty-four patients with oral and pharyngolaryngeal carcinomas underwent surgery were prospective studied to determinate predictors of 2 weeks or longer hospital stay. We studied the impact of malnutrition, tumour location, pharyngeal postoperative problems and infections on hospital stay. RESULTS: 53% of the patients unwent surgery had more than two weeks of hospital stay. Postoperative pharyngeal problems was the strongest correlate of prolonged hospital stay (69% of patients) while only 23% of patients had longer stay because of severe infection (sepsis, neunoniae). Malnutrition or tumor location were not risk factors of prolonged hospitalization stay in our study. CONCLUSIONS: These findings suggest that swallowing problems are the strongest predictors of long hospital stay in head and neck cancer patients.

[Heavy alcohol intake, malnutrition and head and neck cancer patients]. / Ingesta excesiva de alcohol, malnutrición y cáncer de cabeza y cuello.

UNLABELLED: Head and neck cancer patients are frecuently heavy alcohol drinkers. The aim of this study is to determine the impact of alcohol intake on nutritional status and the impact in prognoses. PATIENTS AND METHODS: Fifty patients with oral and pharyngolaryngeal carcinomas were prospective studied in a control-case study. We studied nutritional status and tumoral recurrence in alcoholic and non-alcoholic patients. We also studied alcohol intake after oncologic treatment in these patients. RESULTS: 51% of these patients had excesive alcohol intake before oncologic, treatment. The impact of malnutrition was 70% in alcoholic patients vs 30% in non-alcoholic (p < 0.01). Tumoral recurrence was 30% in alcoholic patients vs 13% in non-alcoholic patients (p < 0.05 ). Only 48% of alcoholic patient stopped alcohol intake after treatment. CONCLUSIONS: Excesive alcohol intake in head and neck cancer patients is a predictive malnutrition factor and it is related to poor prognoses. Alcoholic patients with head and neck cancer and malnutrition need an agresive nutritional, medical and psycosocial support after oncologic treatment, in order to reach a better and longer survival.